The way Flarm works is also dependent on its installation, which as
far as I can see particularly involves the location of the tiny aerial
which gives Flarm to Flarm communication.

My unit is on top of the instrument coaming. This shields it from
transmissions from below, so an approaching glider at a lower level
may be detected some distance away, and then it becomes invisible to
the Flarm unit as it gets close and underneath.

I have also found that on some occasions, a glider has to be really
near before the unit detects it. I don't know why, but it seems to be
somewhat variable.

Nevertheless, I find it very valuable, and these elements of
variability do not make it worthwhile to me to try to develop a
different location for a remote aerial, which in any case would need a
lead that I don't have, although I believe one is available if
required.

Chris N